The relative importance of various traditional determinants of investment (demand, profit, financial and technological constraints) remains insufficiently understood. Although over a long period of time demand appears to be the most important determinant, empirical analyses have shown that, in France, business profitability, and financial constraints, have over the last 20 years significantly influenced the level of investment. An approach focussing on individual investment decisions and drawing directly on business perceptions provides another perspective on the determinant hierarchy. On the one hand, the determinants have asymmetrical effects on the various strategic components of material investment: demand perspectives dominate with regard to increasing production capacities whilst technical factors are more influential as concerns rationalising production processes. On the other hand, the real factors remain the principal driving forces of investment whilst the factors linked to funding only appear in a restrictive sense in investment decisions.